1. Field of the Invention
The present invention relates to driveline systems in motor vehicles, and more particularly to a driveline system having a fixed-angle constant-velocity joint.
2. Description of the Prior Art
In a driveline system for a vehicle such as an automobile, it has long been conventional to employ a single part propeller shaft coupled at its front end by a first universal joint, typically Cardan joint, to a power output shaft of a transmission and at its rear end by a second universal joint to a power input shaft of a differential assembly of the vehicle. Further, it is known to utilize a two part propeller shaft assembly made up from two propeller shaft elements coupled together by a second universal joint, and, as before, coupled at its front end by a first universal joint to the power output shaft of the transmission and at its rear end by a third universal joint to the power input shaft of the differential assembly of the vehicle; this type of two part propeller shaft assembly was introduced in order to reduce the vibration and consequent noise level during high speed operation.
It is known to those skilled in the art that even though universal joints may function at operating angles up to approximately 45xc2x0, they produce cyclic vibrations when operated at joint angles of more than a few degrees (approximately 2xc2x0-3xc2x0). Ordinary Cardan type universal joints cause a change in speed between driving and driven shafts whenever the joint operates at an angle. As the operating angle of the joint increases, the speed (velocity) of the driven shaft varies more and more during each revolution of the shafts. The greater the operating angle, the greater the variation in speed of the driven shaft and the greater the vibration it produces.
However, packaging restraints in present-day vehicles are such that operating angles between the power output shaft of the transmission and the propeller shaft are too large to be feasible in the production of vehicles utilizing conventional universal joints.
Thus, there is a need for a driveline angle reducer that would allow propeller shaft operating angles to be in a range where Cardan joints can be used in the driveline systems without causing excessive cyclic vibrations.
The present invention provides a driveline angle reducer for a driveline system of an automotive vehicle.
The driveline system of the present invention includes at least two propeller shafts and the driveline angle reducer disposed therebetween for drivingly interconnecting the propeller shafts at a fixed operating angle. The driveline angle reducer in accordance with the present invention includes a housing rotatably supporting a fixed-angle constant-velocity joint. The housing of the driveline angle reducer is mounted to a vehicle body and contains a supply of a lubricant for lubrication of the constant-velocity joint.
The novel fixed-angle driveline angle reducer in accordance with the present invention provides the considerably improved driveline system for the motor vehicle that solves vehicle packaging restraints by substantially increasing an angle between the adjacent propeller shafts, while allowing propeller shaft operating angles to be in a range where conventional Cardan joints can be used in the driveline systems without causing excessive cyclic vibrations.